Staying with it-
The other day, I interviewed an older gentleman who told me he and his wife just celebrated 58 years of marriage. I asked him what was their secret of longevity. He told me, "You have to work at it everyday, just like anything that is important to you in life. You will have good days and you will have bad days but overall the good days will win out."
"You just have to make a commitment that you will work at it everyday that's all. No big secret but it also helps to marry your best friend."
That's the secret, you have to work at it everyday just as the old man said. It is no walk in the park but remember happiness is a journey not a destination. Enjoy the journey, every day.